Process for the preparation of detergent alkylate



United States Patent 3,31,210 PRUiCESS FOR THE PREPARATiON 0F DETERGENTALKYLATE George C. Feighner, Oliver C. Kerfoot, David W. Marshall, andThomas E. Howell, Ponca City, 0lrla., assignors to Continental OilCompany, Ponca City, Qkla, a corporation of Delaware No Drawing. FiledFeb. 17, 1965, Ser. No. 433,512 12 Claims. (Cl. 260-671) ABSTRACT OF THEDTSCLOSURE An n-alkyl benzene detergent alkylate composition having adesirably high content of internally substituted phenyl alkanes isproduced by alkylating benzene with a partially chlorinateddetergent-range n-paraffin or mixture thereof in the presence of arecycle stream recovered as a fraction from a previous alkylation run,said fraction being rich in the external phenyl alkane isomers of thehighest molecular weight alkyl benzenes present in the run from whenceobtained.

This invention relates to a process for the preparation of detergentalkylate and more particularly concerns the production of an isomericmixture of detergent grade monophenyl-n-alkane wherein the presence ofinternal isomers predominates. In accordance with the preferredembodiment of this invention, a method is provided for alkylatingbenzene with an n-alkyl halide or straight-chain olefin in the presenceof a recycle product stream having a rich content of the externalisomers of a detergent grade monophenyl n-alkane whereby said isomercontent equilibrates to an isomeric distribution corresponding to thatobtained in the underlying alkylation reaction.

The present invention is directed to the process for preparing alkylbenzenes wherein the alkyl substituents are derived from a detergentgrade linear paraffin or mixture thereof. Such paraffins vary in carbonatom length from about -15. Two related ways are currently favored bythe industry for producing n-alkyl benzenes. Each of these processschemes initially contemplates partially chlorinating a detergent gradeparafiin or mixture thereof to yield a chlorinated product having a highselectivity to monochlorides. The partially chlorinated product itselfcan be used to alkylate benzene in accordance with the Friedel- Craftsreaction or alternately, the product can be dehydrochlorinated to yieldan olefinic alkylating agent. Either process variant results in the samegeneral type of alkylate product. As is well known, the sulfonate saltsof these alkylates are colloidally soluble surfactants. Additionally,these surfactants are biodegradable for which reason they are presentlyof considerable commercial interest.

In order to point up the usefulness of our invention, it would bedesirable to consider briefly the chemical make-up of the detergentalkylates prepared in the foregoing manner. Upon partially chlorinatinga linear paraffin, one obtains a near-statistical distribution of alkylmonochlorides composed of all possible isomers. This distribution is notmaterially altered even upon dehydrochlorinating the product inaccordance with the conventional dehydrohalogenation practices. In thecourse of alkylating benzene with either the partially chlorinatedproduct or dehydrohalogenated derivative thereof, there is obtained analkylate product composed of all the secondary isomers of the alkylbenzene. Essentially no primary alkyl benzenes are formed since theprimary chlorides or alpha olefins present in the alkylating agentisomerize to the secondary form during the alkylation reaction. Thus, asmentioned, the resulting alkylate is an isomeric alkyl benzene icemixture having an equilibrium distribution of all possible secondaryisomers.

It has been found that the various isomers of a given species of alkylbenzene provide surfactants having diiferent detergency properties. Theterm detergency properties not only refers to the actual detersiveability of the surfactant but also contemplates other related propertiesof importance such as foam stability, wetting power and the like.Generally, the detergency properties of any given species of alkylbenzene improves as the phenyl attachment moves toward the center of thealkane chain. The differences noted are of such magnitude that thesulfonate salts of the external secondary isomers of a detergent graden-alkyl benzene are regarded to be comparatively inferior detergents.What constitutes an external isomer depends to a large measure upon theparticular alkyl benzene concerned. In the case of n-decylbenzene,n-hendecylbenzene and n-dodecylbenzene, the term external secondaryisomers contemplates the 2- and B-phenyl isomers; whereas, this termadditionally contemplates the 4-phenyl isomer Where the alkylate iseither n-tridecylbenzene, n tetradecylbenzene or n pentadecylbenzene.Since the boiling point of the various secondary alkyl benzene isomersincreases as the phenyl attachment moves toward the terminal portion ofthe alkane chain, it is possible to recover the bulk of the internalisomers of any particular alkyl benzene by careful distillationpractices.

In our initial efforts directed toward upgrading the external isomers ofan n-alkylbenzene, we found that pure samples of these isomers could bereadily isomerized to yield the normal isomeric distribution uponheating in the presence of a catalytic amount of aluminum chloride. Thelogical extension of this finding was to recycle the external isomersrecovered from an alkylation operation. When this was attempted,however, disappointing results were obtained in that the recycledexternal isomers failed to isomerize with any degree of consistency.

After considerable experimental investigation, it was found thatisomerization catalyst poisoners are generated in the type of alkylationreaction environment with which this invention is concerned andmoreover, that these poisoners are prone to become entrained in thefraction recovered for purpose of recycle. While we have been unable tocharacterize completely these impurities, it appears that they are sometype of condensed or fused ring aromatic compounds. It further was notedthat these compounds are such potent inhibitors that amounts thereofeven in the order of 1% or even lower will effectively inhibit theisomerization of the external isomers present in the recycle fractionunder the conditions normally experienced in the alkylation operation.Efforts to rid contaminated recycle fractions of these impurities bytreatment with agents known to have the ability for preferentiallyabsorbing polynuclear aromatic compounds were of no avail. The key toobtaining satisfactory recycle streams was found to hinge upon observingproper distillation practices in recovering said streams and theimplementation of this finding constitutes the concept behind thisinvention.

In order to facilitate an understanding of the manner of practicing theinstant invention, it warrants reverting to a discussion of the chemicalnature of the alkylation reaction mixtures herein concerned. Aspreviously mentioned, the alkylating agent contemplated is either apartially chlorinated paraffin or mixture thereof or an olefinicmaterial derived therefrom. In preparing such chlorinated products it isnot possible to produce monochlorides exclusively as the formation of aminor amount of dichlorides is inherent in the process. The amount ofdichlorides formed will vary proportionally to the level of chlorinationobserved. For example, at a 10% mole level of chlorination about 95% ofthe total chlorides produced will be monochlorides and at a 40% molelevel the monochloride content decreases to about 80% of the amount ofchlorides formed.

When benzene is alkylated with these partially chlorinated products,part of the dichlorides react with benzene to form alicyclic compounds.The alicyclic compounds produced are believed to be composedpredominately of alkyl substituted 1,2,3,4-tetrahydronaphthalanesalthough there is some evidence that a very minor amount of indanes andother related compounds are produced. The alicyclic type alkylate boilsvery close to the alkyl benzenes having a corresponding carbon atomcontent. Consequently, in order to recover a satisfactory amount of theexternal isomers in a fraction designed to be employed as a recyclestream, it is necessary to include a substantial amount of thecorresponding alicyclic alkylate present in the alkylation reactionmixture. The extent of this recovery, however, is critical since it hasbeen ascertained that fused ring aromatic compounds formed during thealkylation reaction exhibit boiling points overlapping the upper portionof the boiling point range of the alicyclic alkylate corresponding tothe external isomers sought to be recovered.

In accordance with this invention, therefore, a satisfactory recyclefraction is obtained by observing a distillation cut point Within theboiling range of the alicyclic alkylate present in the bottoms fraction.In the case of an alkylate product derived from a single alkane, as muchas 80% but more preferably no more than about 70% of the alicyclicalkylate present can be taken overhead without experiencing any seriouscontamination. Cutting this deep into the bottoms using an efiicientcommercial distillation tower will insure recovery of the bulk of theexternal alkyl benzene isomers present therein. In those instances wherethe alkylation reaction is carried out using a partially chlorinatedalkane mixture, no apt generalization can be made as to the extent thealicyclic alkylate can be taken overhead without the inclusion ofinhibiting amount of impurities. This is so because the boiling pointsof the inhibitors formed under such circumstances more broadly overlapthe boiling point range of the alicyclic alkylate corresponding toexternal isomers desired to be recovered. Accordingly, in suchsituations the best approach is to determine experimentally for eachsystem faced the extent of recovery applicable. To do this, one needonly periodically check the overhead to determine the point at whichobjectional amounts of the inhibitors are being entrained. A simplearbitrary test for this purpose consists of periodically taking aportion of the overhead and heating same at a temperature of from about40 to 80 C. in the presence of about AlCl This isomerization test isdesirably conducted in a medium of benzene in order to obviate anydisproportionation of the alkyl benzenes. Suitable amounts of benzenerange from about 1 to parts per part of the overhead. When suchtreatment first fails to result in more than about 75% isomerization ofthe external isomer content within a time period not exceeding aboutthirty minutes, then this will indicate that the applicable recycle cutpoint has been approximately reached.

Basically, the testing procedure described indicates that theaccumulated fraction rich in external isomers will effectively isomerizewhen recycled to a conventional alkylation operation. Obviously manymodifications of this test will sufiice and possibly other proceduressuch as, for example, UV analysis, can be devised to provide the sameinformation. Of course, in any continuous operation the proper cut pointwill be maintained at a given predetermined distillation temperature.

Suitable fractions rich in external isomers obtained as described abovecan be recycled to a reaction mixture undergoing alkylation in whole orin part. As an alternative to recycling the recovered external isomers,same can be isomerized by treatment with AlCl and thereupon the internalisomers resulting from a direct isomerization procedure of this type canbe recovered by distillation. A suitable amount of AlCl for effectingdirect isomerization is from about 2 to 10% based on the weight of thetotal fraction subjected to treatment. Satisfactory isomerizationtemperatures range from about 40 to C. As indicated above, it ispreferred to carry out the isomerization reaction in the presence offrom about 1 to 25 parts benzene.

The much more preferred procedure from an economical standpoint forupgrading the fractions containing a rich content of external isomers,however, is to recycle them to an alkylation reactor as has beenindicated throughout the previous discussion. Conventional alkylationpractices are applicable in effecting the isomerization of a fraction ofexternal isomers constituting an internal recycle stream to analkylation reaction system. The general aspects of such practices willbe discussed next.

Partially chlorinated products suitable for use in the alkylationprocess to which this invention is directed can be obtained by reactingbetween about 0.1 and 0.4 mole of chlorine per mole of paraffin. Withinthis range satisfactory selectivities to monochloride formation can be.realized. Conventional methods for effecting the chlorination reactioncan be observed, i.e., either liquid or vapor phase chlorination isapplicable. The reaction can be either catalytically or thermallyinduced. The whole of the partially chlorinated product ordehydrohalogenated derivative thereof is customarily charged to thealkylation reaction sphere as it is too difiicult to separate theconverted parafiins from the unreacted parafiins.

A catalyst is required to effect the reaction between alkyl chlorides orolefins and an alkylatable compound, here specifically benzene. Avariety of Friedel-Crafts catalysts are applicable. An enumeration ofsuch catalysts include aluminum chloride, iron chloride, zinc chloride,titanium chloride, hydrofluoric acid, boron trifiuoride, and the like.The preferred catalyst is aluminum chloride. In order to isomerizeexternal isomers present in the alkylation reaction mixture as recycledmaterial, it is necessary to use AlCl as the alkylation catalyst.Amounts of the aluminum chloride that can be used range from betweenabout 1 and 10% based upon the amount of alkyl chlorides present in thereaction mixture. An especially preferred catalyst system consists ofaluminum chloride in admixture with catalyst sludge obtained from aprevious alkylation run employing said aluminum salt as the catalyst.This affords use of substantially less aluminum chloride than isordinarily needed to effect a given rate for th alkylation reaction. Inthe event the alkylating agent is an alkyl chloride, another advantageof using sludge is that aluminum powder can be incorporated in thesludge and such a mixture under the conditions of reaction encounteredwill provide for the in situ formation of aluminum chloride enrichedsludge.

The alkylation temperature can be varied over wide limits ranging fromabout room temperature to 80 C. A preferred range is in the order fromabout 40-80 C.

The ratio of benzene to alkyl chlorides or olefins present in thereaction mixture can also be varied over wide limits. Applicable ratiosare from about 1 to 20 moles benzene to 1 mole of alkyl chloride orolefin. On the aftersaid basis, a preferred range of benzene to alkylchloride or olefin is from about 5:1 to 10:1, respectively. Thealkylation reaction can be carried out in a continuous or batch manner.In either type of operation, an effective reaction time is from about 15to minutes. The precise time needed for effecting substantially completealkylation is dependent upon a number of factors, including the amountof catalyst used, ratio of benzene to alkylating agent, temperature,etc. The course of the reaction can be readily followed by analyzing fororganic chloride.

Following the alkylation reaction, it is ordinarily advantageous totreat the effluent with aqueous sulfuric acid followed by washing withcaustic solution. Following this preliminary purification step,unreacted benzene is first stripped from the reaction effluent. Next,the unreacted paraffins present in the stripped mixture are removed. Thereaction product is then fractionated to yield a desired composition ofinternal isomers and thereupon a fraction rich in external isomers isrecovered in a manner described hereinabove for purposes of recycle ordirect treatment with aluminum chloride to effect isomerization of theexternal alkyl benzene isomers present therein.

In order to illustrate further to those skilled in the art the nature ofthis invention and how it can be practiced, the following specificexamples are given. As indicated, these examples are set forth primarilyfor the purposes of illustration and accordingly, any enumeration ofdetails contained therein should not be interpreted as a limitation onthe invention except as such are expressed in the appended claims. Allparts are parts by weight unless otherwise indicated.

EXAMPLE I For the purpose of illustrating the nature of theisomerization catalyst inhibitors formed in the type of alkylationprocedure with which this invention is concerned, alkylation runs No. 1and No. 2 were conducted using as the alkylating agent a partiallychlorinated n-dodecane and a partially chlorinated mixture of C -Clinear paraffins, respectively. Each partially chlorinated productcontained about 4% combined chlorine representing about a 20% level(mole) of chlorination. In each run a benzene/alkylchloride mole ratioof 8:1, respectively, was observed and the amount of aluminum chloridealkylation catalyst was 4% based on the alkylchloride content of thealkylating agent. The alkylation reaction was carried out at 65 C.

Following alkylation, the reaction mixtures were stripped of unreactedbenzene and parafiins. Thereupon, the alkylate product of each run wasfractionated to yield various cuts or fractions selected to showapproximately where the isomerization inhibitors occur in the product interms of its boiling point characteristics. A portion of each cutcollected was combined with an equal part of pure 2-phenyl isomer andthe mixtures were then isomerized; whereupon, the extent ofisomerization of the added Z-phenyl isomer was noted. In order tosimplify analysis, a pure Z-phenyl tetradecane sample was employed intesting the various fractions comprising run No. 1 whereas pure 2-phenyldodecane was used in testing the selected fractions of run No. 2. Theconditions observed in carrying out the isomerization reaction werestandardized using 2 parts of benzene per part of combined alltylateproduct and added 2-phenyl isomer and 10% AlCl based on the latter. Theisomerization reaction was conducted at 65 C. for 20 minutes. Thecompositions of the various cuts and results obtained are set out asfollows:

tion of a tetradecylbenzene product to simplify the analyses needed forillustrating various pertinent features thereof.

To a suitable reaction vessel equipped with a stirrer and heating meanswere charged 7170 parts of a partially chlorinated n-tetradecane. Thepartially chlorinated product contained 4.53% chlorine and was preparedby chlorinating tetradecane in the liquid phase. Additionally charged tothe reaction vessel were 7180 parts benzene and 107 parts aluminumchloride. These reactants were held at C. for minutes with stirring.Following alkylation, the reaction mixture was permitted to settle,whereupon the catalyst sludge was removed. The reaction mixture was thenwashed with 5% concentrated sulfuric acid, followed by washing withcaustic soda solution to remove all traces of acid. The partiallypurified reaction mixture was then distilled to yield the followingfractions:

No. Fraction Dist. Temp, 0., Wt.

10 mm. Hg. (parts) 1 Excess benzene Excess tctradecane.. 124*184 5, 360184-193 750 193-207 617 5 Bottoms 220 The compositions of fractions 3and 4- were determined to be as follows:

The Z-phenyl isomer content of the total alkylate (fractions 3 and 4combined) was 30.6% when normalized on a monoalkylbenzene basis.

A second alkylation run was conducted in which the 2- phenyl isomer richfraction 4 was employed as a recycle stream. Into an alkylation reactionvessel such as described above were charged 5352 parts of chlorinatedtetradecane (4.95% chlorine), 5800 parts benzene, 86 parts aluminumchloride, and 396 parts of fraction 4. The alkylation conditionsemployed here corresponded essentially to those described above inconnection with the previous run.

Following catalyst removal and partially purifying the reaction mixtureas previously described, said mixture was then fractionated to yield thefollowing:

TABLE I Run Cut Dist. Temp. Composition Isorneri- No. No. zation,

percent 115 HEP-259" F. (2.5 mm. Hg)... 11.2, Cm alicyclic alkylate 16259266 F C alicyclic alkylate 65 18 288-340 F". do 0 20 345-347 F...Diphenyl dodecane.. 83 21 347-35 F o 39 1 385 F. (10 mm Hg) External (#03, internal C 100 2 385- F 297fkinlttci 51% 2-O14, 19% C14 alicyelic 100E y 8. 8. 3 390 400 F 5% int. 48C, 49% 2-G 4, 46% CH alieyclie 100alkylatc. 4 400-420 F 98% C14 alicyclic alkylate" 0 Represents about 40%of total 014 alicyclic alkylate present.

EXAMPLE II 70 No. Fraction Dist Tempfi 0., Wt. The purpose of thisexample is to illustrate the lmmm g (parts) proved results to beobtained with regard to product 6 Excess benzene Mli yield by utilizingan undesirable by-product as an inter- 5 nal recycle stream inaccordance with this lnventlon. The 9 191-207 928 10 Bottoms 158 presentexample is limited to a process for the prepara- The composition of eachof the alkylate product fractions 8 and 9 was determined to be asfollows:

Isomer Distribution Fraction 8, Fraction 9,

Percent Percent Alkyl substituted 1,2,3,4-tetrahydronaph thalenes 1. 19.3 2-phenyl tetradecaue 2. 2 41. 0 3,4,5,G,7-phenyl totradecane 913. 738. 9

EXAMPLE III This example serves to illustrate the improved detersiveproperties exhibited by detergent compositions derived from monophenylalkane mixtures which can be economically obtained in the practice ofthis invention.

Five alkylation runs were conducted wherein the respective alkylatingstocks were various mixtures of ndodecane, n-tridecane andn-tetradecane, all of which were chlorinated to approximately twentymole percent. The molar ratio of alkyl chloride to benzene and thevarious other alkylation conditions employed were substantiallyidentical to those conditions observed in Example II. In the initial tworuns of this series, the respective alkylate products were distilled toyield fractions containing essentially all of the Z-phenyl tctradecanecomponent of the alkylation reaction mixture. In the three subsequentruns the respective alkylation reaction mixtures were fractionallydistilled, as was done in Example II, to recover monophenyl alkanefractions substantially free of 2-phenyl tetradecane. All of thesealkylate products were sulfonated with 20 percent oleum and thenneutralized with a caustic soda solution. The resultant sulfonate saltswere compounded into a typical heavy-duty detergent composition composedof 22% of the sulfonate salt, 56% of tripolyphosphate, 17% of sodiumsulfate and sodium silicate. Foam stability of these severalcompositions was determined using the standard dishwashing test wherein0.112 percent of the compounded detergent composition was added to waterat 115 C. and thereupon uniformly soiled plates were washed until therewas a permanent break in the foam covering the dishwashing pan. Thistest was conducted at two hardness levels. The results of this test areset forth in the following Table II.

What is claimed is:

1. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a hydrocarbon selectedfrom the group consisting of C -C linear paraffins and mixtures thereofat a temperature from about C. to 80 C. in the presence of from aboutl10% AlCl based on the alkyl chloride content of said chlorinationproduct and in the presence of the hereinbelow-defined recycle stream,distilling the alkylation reaction mixture to recover successively adetergent alkylate fraction consisting of a mixture of secondarymonophenyl alkane isomers containing a substantially reduced amount ofthe external secondary isomers of the highest molecular weight phenylalkane present in the alkylation reaction mixture and a higher boilingsecond fraction constituting said recycle stream consisting of a mixtureof said external isomers and corresponding alicyclic alkylate butcontaining not in excess of that amount of the alicyclic alkylate whichwill result in the inclusion in said second fraction of an amount of thefused ring aromatic compounds present in the reaction mixture whichwould inhibit the isomerization of the external isomers under thealkylation conditions hereinabove described.

2. A process for the preparation of detergent alkylate which comprisesreacting an excess of benzene at a temperature from about 20 to 80 C.with an alkylating agent obtained by dehydrohalogenating a chlorinationproduct of from about 0.1 to 0.4 mole of chlorine and a mole of ahydrocarbon selected from the group consisting of C C linear paraffinsand mixtures thereof in the presence of from about 110% AlCl based onthe olefin content of the dehydrohalogenated derivative and in thepresence of the hercin below-defined recycle stream, distilling thealkylation reaction mixture to recover successively a detergent alkylatefraction consisting of a mixture of secondary monophenyl alkane isomerscontaining a substantially reduced amount of the external secondaryisomers of the highest molecular weight phenyl alkane present in thealkylation reaction mixture and a higher boiling second fractionconstituting said recycle stream consisting of a mixture of saidexternal isomers and corresponding alicyclic alkylate but containing notin excess of that amount of the alicyclic alkylate which will result inthe inclusion in said second fraction of an amount of the fused ringaromatic compounds present in the reaction mixture which would inhibitthe isomerization of the external isomers under the alkylationconditions hereinabove described.

3. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a linear parafi'inhaving a carbon atom length of from 1015 at a temperature from about 40to 80 C. in the presence of from about 1-10% AlCl based on the alkylchloride content of said chlorination product and in the presence of thehereinbelowdefined recycle stream, distilling the alkylation reactionmixture to recover successively a detergent alkylate fraction consistingof a mixture of the secondary isomers of the monophenyl alkane andcontaining a substantially reduced amount of the external isomersthereof present in the alkylation reaction mixture and a higher boilingsecond fraction constituting said recycle stream consisting of a mixtureof said external isomers and not in excess of about of the allcyclicalkylate present in the alkylation reaction mixture.

4. A process for the preparation of detergent alkylate which comprisesreacting an excess of benzene at a temperature of from about 40 to C.with an alkylating agent obtained by dehydrohalogenating a chlorinationproduct of from about 0.1 to 0.4 mole of chlorine and a mole of a linearparafiin having a carbon atom length of from 10-15 in the presence offrom about 1-10% AlCl based on the olefin content of thedehydrohalogenated derivative and in the presence of thehereinbelowdefined recycle stream, distilling the alkylation reactionmixture to recover successively a detergent alkylate fraction consistingof a mixture of the secondary isomers of the monophenyl alkane andcontaining a substantially reduced amount of the external isomersthereof present in the alkylation reaction mixture and a higher boilingsecond fraction constituting said recycle stream consisting of a mixtureof said external isomers and not in excess of about 70% of the alicyclicalkylate present in the alkylation reaction mixture.

5. A process for the preparation of internal secondary isomers of amonophenyl alkane which comprises alkylating an excess of benzene with achlorination product of from about 0.1 to 0.4 mole of chlorine and amole of a linear paraffin having a carbon atom length of from 10-15 at atemperature from about 40 to 80 C. in the presence of from about 140%AlCl based on the alkyl chloride content of said chlorination product,distilling the alkylation reaction mixture to recover successively afirst fraction consisting of a mixture of the secondary isomers of themonophenyl alkane product and containing a substantially reduced amountof the external isomers thereof present in the alkylation reactionmixture and a higher boiling second fraction consisting of said externalisomers and not in excess of about 70% of the alicyclic alkyla-tepresent in the alkylation reaction mixture, heating said second fractionat a temperature between about 40 and 80 C. in the presence of fromabout 1 to 25 parts benzene and from 1-10% AlCl to effect substantiallycomplete isomerization of the external isomer content and thereupondistilling said isomerized product to recover a mixture of monophenylalkane isomers having an isomeric distribution corresponding about tothat of said first fraction.

6. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a C -C linear paraflinat a temperature from about 40 to 80 C. in the presence of from about1-10% AlCl based on the alkyl content of said chlorination product andin the presence of the hereinbelow-defined recycle stream, distillingthe alkylation react-ion mixture to recover successively a detergentalkylate fraction essentially free of the Z-phenyl isomer and containinga substantially reduced amount of the 3-phenyl isomer present in thealkylation reaction mixture and a higher boiling second fractionconstituting said recycle stream consisting of said 2- and 3-phenylisomers and corresponding alicyclic alkylate but containing not inexcess of that amount of the alicyclic alkylate which will result in theinclusion in said second fraction of an amount of fused ring aromaticcompounds present in the reaction mixture which would inhibit theisomerization of the external isomers under the alkylation conditionshereinabove described.

7. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a C -C linear paraffinat a temperature from about 40 to 80 C. in the presence of from about1-10% AlClbased on the alkyl chloride content of said chlorinationproduct and in the presence of the herein'below-defined recycle stream,distilling the alkylation reaction mixture to recover successively adetergent alkylation fraction essentially free of the 2- phenyl isomerand containing a substantially reduced amount of the 3-phenyl isomerpresent in the alkylation reaction mixture and a higher boiling secondfraction constituting said recycle stream consisting of said 2- and3-phenyl isomers and not in excess of about 70% of the alicyclicalkylate present in the alkylation reaction mixture.

8. A process for the preparation of internal secondary isomers of amonophenyl alkane which comprises alkylating an excess of benzene with achlorination product of from about 0.1 to 0.4 mole of chlorine and amole of a C -C linear paraffin at a temperature from about 40 to 80 C.in the presence of from about l% AlCl based on the alkyl chloridecontent of said chlorination product, distilling the alkylation reactionmixture to recover successively a detergent alkylate fractionessentially free of the Z-phenyl isomer and containing a substantiallyreduced amount of the S-phenyl isomer present in the alkylation reactionmixture and a higher boiling second fraction consisting of said 2- and3-phenyl isomers and not in excess of about 70% of the alicyclicalkylate present in the alkylation reaction mixture, heating said secondfraction at a temperature between about 40 and 80 C. in the presence offrom about 1 to 25 parts benzene and from 110% AlCl to effectsubstantially complete isomerization of the external isomer content andthereupon distilling said isomerized product to recover a mixture ofmonophenyl alkane isomers having an isomeric distribution correspondingabout to that of said first fraction.

9. A process for the preparation of detergent alkylate which comprisesalkyl'ating an excess of benzene With a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a C C linear parafiin ata temperature from about 40 to 80 C. in the presence of from about 110%AlCl based on the alkyl content of said chlorination product and .in thepresence of the hereinbelow-defined recycle stream, distilling thealkylation reaction mixture to recover successively a detergent alkylatefraction essentially free of the 2- and 3-phenyl isomers and containinga substantially reduced amount of the 4-phenyl isomer and a higherboiling second fraction constituting said recycle stream consisting of amixture of said 2-, 3-, and 4-phenyl isomers and corresponding alicyclicalkylate but containing not in excess of that amount of the alicyclicalkylate which will result in the inclusion in said second fraction ofan amount of fused ring aromatic compounds present in the reactionmixture which would inhibit the isomerization of the external isomersunder the alkylation conditions hereinab'ove described.

10. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with a chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a C C linear parafiin ata temperature from about 40 to 80 C. in the presence of from about 1-10%AlCl based on the alkyl chloride con-tent of said chlorination productand in the presence of the hereinbelow-defined recycle stream,distilling the alkylation reaction mixture to recover successively adetergent alkylate fraction essentially free of the 2- and 3-phenylisomers and containing a substantially reduced amount of the 4-phenylisomer and a higher boiling second fraction constituting said recyclestream consisting of a mixture of said 2-, 3-, and 4-phenyl isomers andnot in excess of about of the alicyclic alkylate present in thealkylation reaction mixture.

11. A process for the preparation of internal secondary isomers of amonophenyl alkane which comprises alkylating an excess of benzene with achlorination product of from about 0.1 to 0.4 mole of chlorine and amole of a C -C linear paraffin at a temperature from about 40 to C. inthe presence of from about 1-10% AlCl based on the alkyl chloridecontent of said chlorination product, distilling the alkylation reactionmixture to recover successively a detergent .alkylate fractionessentially free of the 2- and 3-phenyl isomers and containing asubstantially reduced amount of the 4-phenyl isomer and a higher boilingsecond fraction consisting of a mixture of said 2-, 3-, and 4-phenylisomers and not in excess of about 70% of the alicyclic alkylate presentin the alkylation reaction mixture, heating said second fraction at atemperature between about 40 and 80 C. in the presence of from about 1to 25 parts benzene and from 1-10% AlCl to effect substantially completeisomerization of the external isomer content and thereupon distillingsaid isornerized product to recover a mixture of monophenyl alkaneisomers having an isomeric distribution corresponding about to that ofsaid first fraction.

12. A process for the preparation of detergent alkylate which comprisesalkylating an excess of benzene with the chlorination product of fromabout 0.1 to 0.4 mole of chlorine and a mole of a mixture of at leasttwo but not in excess of four adjacent members of homologous series of C-C linear paratfins at a temperature of from about 40 to 80 C. in thepresence of from about 110% AlCl based on the alkyl chloride content ofsaid chlorin-ation product and in the presence of thehereinbelow-defined recycle stream, distilling the alkylation reactionmixture to recover successively a detergent alkylate fraction consistingof a mixture of secondary monophenyl alkane isomers containing asubstantially reduced amount of the external secondary isomers of thehighest molecular weight phenyl alkane present in the alkylationreaction mixture and a higher boiling second fraction constituting saidrecycle stream consisting of a mixture of said external isomers andcorresponding alicyclic alkylate but containing not in excess of thatamount of the alicyclic alkylate which will result in the inclusion insaid second fraction of an amount of fused ring aromatic compoundspresent in the reaction mixture' which would inhibit the isomerizationof the external isomers under the alkylation conditions hereinabovedescribed.

Olson: Industrial and Engineering Chemistry, vol. 52, No. 10, October1960, pp. 833 836.

Swisher et al.: I. of Organic Chem., vol. 26, October DELBERT E. GANTZ,Primary Examiner.

PAUL M. COUGHLAN, IR., Examiner.

C. R. DAVIS, Assistant Examiner.

